CN114032351B - Production control method for efficiently utilizing iron oxide in converter slag - Google Patents
Production control method for efficiently utilizing iron oxide in converter slag Download PDFInfo
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- CN114032351B CN114032351B CN202111396165.1A CN202111396165A CN114032351B CN 114032351 B CN114032351 B CN 114032351B CN 202111396165 A CN202111396165 A CN 202111396165A CN 114032351 B CN114032351 B CN 114032351B
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/36—Processes yielding slags of special composition
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/30—Regulating or controlling the blowing
- C21C5/32—Blowing from above
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Abstract
The invention discloses a production operation control method for efficiently utilizing iron oxide in converter slag, which solves the difficult problems of large lime addition amount, low lime utilization rate, high consumption, high cost, large slag viscosity, even deteriorated dephosphorization, high iron oxide (FeO), high steel material consumption and increased cost, improves the economic and technical indexes of converter production and operation, reduces the converter smelting cost, improves the converter smelting efficiency, and provides basic guarantee for low-cost and high-efficiency production of converter steelmaking.
Description
Technical Field
The invention relates to the technical field of ferrous metallurgy, in particular to a production control method for efficiently utilizing iron oxide in converter slag.
Background
The converter steelmaking process is an oxidation decarburization process for generating CO/CO2 gas for decarburization by blowing high-purity oxygen into a molten metal bath containing high-carbon high-phosphorus molten iron, and a dephosphorization process for combining CaO contained in slag materials such as lime, dolomite and the like with P2O5 generated by oxidation. In the range with proper alkalinity, the more lime is added, the higher the phosphorus removal rate is, but the more lime is added, the consumption is high, the cost is high, and the more lime is added, the slag viscosity is high, the lime utilization rate is low, and even the dephosphorization is deteriorated. In a proper alkalinity range, the effective means for reducing the addition of lime and improving the lime utilization rate is to improve the content of iron oxide (FeO) in slag, the slag melting can be promoted due to the high content of iron oxide (FeO) in slag, but the consumption of steel materials is increased due to the high content of iron oxide (FeO), namely the cost is increased. Therefore, in order to solve this contradiction, controlling the iron oxide (FeO) content of the slag at different stages of the converter becomes a key to the control of the smelting operation process of the converter.
Disclosure of Invention
The invention aims to provide a production control method for efficiently utilizing iron oxide in converter slag, which solves the difficult problems of large lime addition amount, low lime utilization rate, high consumption, high cost, large slag viscosity, even aggravated dephosphorization, high iron oxide (FeO), high steel material consumption and increased cost in the background art, improves the economic and technical indexes of converter production and operation, reduces the converter smelting cost, improves the converter smelting efficiency, and provides a basic guarantee for the low-cost and high-efficiency production of converter steelmaking.
In order to solve the technical problems, the invention adopts the following technical scheme:
the invention relates to a production control method for efficiently utilizing iron oxide in converter slag, which comprises the following steps:
s1, controlling the content of high iron oxide (FeO) in the slag at the early stage and the middle stage in the smelting process of the converter
Wherein:
the converter smelting is divided into three stages of an early stage, a middle stage and a later stage, the oxygen blowing smelting time of the converter is generally 15min, and the early stage is generally as follows: 0-5min, the middle stage is: 5-12min, the earlier stage is: 12-15min;
the control of the lance position of the oxygen lance is divided into a low lance position, a middle lance position and a high lance position, wherein the range of the low lance position is as follows: 1.5-1.8m, and the range of the middle gun position is as follows: 1.8-2.5m, the high gun position range is as follows: 2.5-3.0m;
the bottom blowing air supply intensity of the converter is designed to be 0.15Nm3T min, and simultaneously dividing the bottom blowing strength of the converter into high, medium and low bottom blowing strengths, wherein the low bottom blowing strength range is as follows: 0.02-0.05Nm3T min, the middle sole blowing strength range is as follows: 0.05-0.10Nm3T min, high bottom blowing intensity range: 0.10-0.15Nm3/t·min；
The angle of the oxygen lance nozzle of the medium-sized and small-sized converter which is less than 200 tons is controlled between 12 degrees and 15 degrees, the angle of the oxygen lance nozzle of the large converter which is more than 200 tons is controlled between 14 degrees and 16 degrees;
s1.1 method for controlling content of high iron oxide (FeO) in early stage of converter
In the earlier stage of converter smelting, the lance position of the oxygen lance is controlled by alternately controlling a high lance position and a low lance position, wherein the high lance position is used for quickly increasing the content of iron oxide (FeO) in slag to enable the content to quickly reach more than 20 percent; then, the low lance position control is adopted, so that the temperature of the molten pool is uniformly raised as soon as possible, and meanwhile, the early low-temperature splashing of the converter is prevented; the bottom blowing strength control adopts middle-high bottom blowing gas supply strength for full stirring, the dynamic condition of a molten pool is improved, lime melting is promoted, and early-stage rapid slagging and dephosphorization are realized;
s1.2 method for controlling content of high iron oxide (FeO) in middle stage of converter
In the middle stage of converter smelting, the lance position of the oxygen lance is controlled by adopting a middle lance position range, and the middle lance position and the high lance position are controlled alternately to keep the content of iron oxide (FeO) in the slag and keep the content of the FeO between 18 and 25 percent; forbidding long-time high lance position control to prevent the foam slag of the slag with overhigh content of iron oxide (FeO) from splashing; forbidding long-time low-lance position control, and preventing the return drying of iron oxide (FeO) slag with low content from sticking a lance and metal splashing; the carbon-oxygen reaction of the molten pool is violent in the middle stage of smelting, the stirring intensity of the molten pool is sufficient, the bottom blowing intensity is controlled by adopting middle-low bottom blowing gas supply intensity to supplement stirring, the rapid melting of newly added lime is promoted, and the effects of rapid slag melting in the middle stage and dephosphorization in the early stage of protection are realized;
s2, controlling the content of low iron oxide (FeO) in slag in the later period of the converter
In the later stage of converter smelting, the lance position of the oxygen lance is controlled in a low lance position range, so that the content of iron oxide (FeO) in slag is reduced, the content of the FeO is kept below 18 percent or even lower, the consumption of steel materials is reduced, and the smelting cost is reduced; high lance position control is prohibited for a long time in the later period, and the problem that the converter production and production accidents are influenced because the foam slag of the slag with the excessive content of iron oxide (FeO) cannot be subjected to end-point carbon-pulling converter deslagging and tapping operation is avoided; in the later stage of smelting, the carbon-oxygen reaction of the molten pool is weakened, the stirring strength of the molten pool is reduced, the bottom blowing strength is controlled by adopting high bottom blowing gas supply strength to carry out reinforced stirring, so that the content of iron oxide (FeO) in the slag is reduced as soon as possible, and the low-cost production control target of the low-iron oxide (FeO) slag in the later stage is realized.
Compared with the prior art, the invention has the following beneficial technical effects:
the method adopts different converter smelting means and methods to control the content of iron oxide (FeO) in the slag at different stages of the converter smelting process; the high iron oxide (FeO) content in the early and middle stages of the converter is controlled, the quick melting of lime is promoted, the utilization rate of the lime is improved, and the aims of reducing the consumption of the lime and efficiently dephosphorizing are fulfilled; the content of low iron oxide (FeO) in the later period is controlled, the consumption of steel materials is reduced, and the aim of reducing the cost is fulfilled.
Drawings
The invention is further illustrated in the following description with reference to the drawings.
FIG. 1 shows the lance position control mode of the oxygen lance.
Detailed Description
In order to make the aforementioned aspects, features and advantages of the present invention more clearly understandable, a production control method for efficient utilization of iron oxide in converter slag according to the present invention will be described in further detail with reference to specific embodiments.
1 iron oxide (FeO) promoting slagging mechanism
The main component of lime is calcium oxide (CaO), which has a melting point of about 2580 ℃ and is a high-melting-point substance. The converter bath temperature range is generally between 1200 ℃ and 1700 ℃, and lime cannot be melted in the converter bath temperature range. When calcium oxide (CaO) and silicon dioxide (SiO) in slag2) When different compounds are generated by the reaction, the melting point is reduced, but the melting point is between 1500 and 2100 ℃, the melting speed is slow, a large amount of time is needed, and the production efficiency of the converter is influenced.
When the iron oxide (FeO) content in the slag is increased, the iron oxide (FeO) ions (Fe)2+、Fe3+、O2-) The radius is not large, the crystal system is cubic like CaO, feO is favorably transferred and diffused to lime crystal lattices, and a low-melting-point substance (CaO. SiO) is generated2FeO) and molten; the content of iron oxide (FeO) in the slag is high, and 2CaO SiO on the surface of the lime blocks can be reduced2Can make the generated 2 CaO. SiO2Loosening, detachment and fusion; the content of iron oxide (FeO) in the slag is high, the wetting of the slag to lime and the permeation of the slag into lime gaps are improved, the viscosity of the slag is obviously reduced, the mass transfer of lime blocks is accelerated, and the lime is favorably dissolved.
2 optimizing the angle of the oxygen lance nozzle and providing better slagging conditions
The angle of the oxygen lance nozzle of the converter is generally between 12 and 16 degrees, the angle of the oxygen lance nozzle of a medium-sized and small converter which is less than 200 tons is generally between 12 and 15 degrees, the angle of the oxygen lance nozzle of a large converter which is more than 200 tons is generally between 14 and 16 degrees.
The oxygen lance nozzle with a large angle is adopted within a reasonable range, the angle of the oxygen lance nozzle is large, the area blown into a metal molten pool is large, the reaction speed of blown high-purity oxygen and carbon (C) of the metal molten pool is slow, excessive oxygen and iron react to generate iron oxide (FeO), the content of the iron oxide (FeO) in slag is improved, the iron oxide (FeO) in slag reacts with calcium oxide (CaO) to generate a (CaO. FeO) low-melting-point substance, the quick melting of lime is promoted, and the purposes of quick slag melting and high-efficiency dephosphorization are realized.
3 description of three-stage converter smelting, oxygen lance position and bottom blowing strength
The converter smelting is divided into three stages, namely an early stage, a middle stage and a later stage, the oxygen blowing smelting time of the converter is generally 15min, and the early stage is generally as follows: 0-5min, the middle stage is: 5-12min, the early stage is: 12-15min.
The lance position of the oxygen lance is the vertical distance between a nozzle of the oxygen lance and the liquid level of the metal molten pool in the oxygen blowing process of converter smelting; the control of the oxygen lance position is generally divided into a low lance position, a middle lance position and a high lance position, the height of the oxygen lance position is not completely and clearly defined, but the range of the low lance position is as follows: 1.5-1.8m, the middle gun position range is as follows: 1.8-2.5m, the high gun position range is as follows: 2.5-3.0m.
The bottom blowing strength is the bottom blowing gas supply strength of the converter, and the general bottom blowing strength is designed to be 0.15Nm3The bottom blowing strength is generally divided into high, medium and low bottom blowing strengths, the level of the bottom blowing strength is not completely defined, but the low bottom blowing strength range is generally as follows: 0.02-0.05Nm3T min, the middle sole blowing strength range is as follows: 0.05-0.10Nm3T min, high bottom blowing intensity range: 0.10-0.15Nm3T.min; but at present, the number of individual manufacturers can reach 2.0Nm3T.min, even 4.0Nm3Ultra-high bottom blowing strength at/t min.
4 method for controlling high iron oxide (FeO) content in early stage and middle stage of converter
In the earlier stage of converter smelting, the lance position of the oxygen lance is controlled by alternately controlling a high lance position and a low lance position, wherein the high lance position is used for quickly increasing the content of iron oxide (FeO) in slag to enable the content to quickly reach more than 20 percent; and then, the low lance position control is adopted, so that the temperature of the molten pool is uniformly raised as soon as possible, and meanwhile, the early low-temperature splashing of the converter is prevented. The bottom blowing strength control adopts the middle-high bottom blowing gas supply strength to fully stir, improves the dynamic condition of a molten pool, promotes lime melting, and realizes rapid slagging and dephosphorization in the previous period.
In the middle stage of converter smelting, the lance position of the oxygen lance is controlled by adopting a middle lance position range, and the middle lance position and the high lance position are controlled alternately to keep the content of iron oxide (FeO) in the slag and keep the content of the FeO between 18 and 25 percent; long-time high lance position control is forbidden, and foam slag of slag with excessive iron oxide (FeO) content is prevented from splashing; and long-time low-lance position control is forbidden, and dry sticking and metal splashing of the slag with low content of iron oxide (FeO) are prevented. The carbon-oxygen reaction of the molten pool is violent in the middle stage of smelting, the stirring intensity of the molten pool is sufficient, the bottom blowing intensity is controlled by adopting middle-low bottom blowing gas supply intensity to supplement stirring, the rapid melting of newly added lime is promoted, and the effects of rapid slag melting in the middle stage and phosphorus removal in the early stage of protection are realized.
4 method for controlling content of late low iron oxide (FeO)
In the later stage of converter smelting, the lance position of the oxygen lance is controlled by adopting a low lance position range, so that the content of iron oxide (FeO) in slag is reduced, the content of the iron oxide is kept below 18 percent or even lower, the consumption of steel materials is reduced, and the smelting cost is reduced; and the long-time high lance position control in the later period is forbidden, so that the condition that the foam slag of the iron oxide (FeO) slag with too high content cannot be subjected to the end-point carbon-pulling converter deslagging and tapping operation, and the converter production and the production accidents are influenced is prevented. In the later stage of smelting, the carbon-oxygen reaction of the molten pool is weakened, the stirring strength of the molten pool is reduced, the bottom blowing strength is controlled by adopting high bottom blowing gas supply strength to carry out reinforced stirring, so that the content of iron oxide (FeO) in the slag is reduced as soon as possible, and the low-cost production control target of the low-iron oxide (FeO) slag in the later stage is realized.
As shown in FIG. 1, an exemplary lance position control mode is provided. According to the phosphorus content and dephosphorization efficiency of the molten iron, the operation control can be properly changed, namely when the phosphorus content of the molten iron is low and the dephosphorization efficiency is high, the lower lance position and the higher bottom blowing strength can be adopted for control, so that the content of iron oxide (FeO) in the slag is further reduced, the smelting cost is further reduced, and the high-efficiency production control target of the converter with lower cost is achieved.
5 overview
Through the implementation of the production control method, the difficult problems of low lime utilization rate, high consumption, high cost, high slag viscosity, even deteriorated dephosphorization and high iron oxide (FeO) consumption, high steel material consumption and increased cost in the background technology are solved, the economic and technical indexes of converter production operation are improved, the dynamic production control effect of the iron oxide (FeO) content in the slag in different periods of the converter smelting process is realized, namely the high iron oxide (FeO) content in the slag is utilized in the early stage of smelting to promote the quick lime melting, the iron oxide (FeO) content in the slag is quickly reduced in the later stage of smelting, the high-efficiency production control target of reducing the steel material consumption and the production cost of the converter is achieved, and the basic guarantee is provided for the high-quality converter steelmaking production.
The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.
Claims (1)
1. A production control method for efficiently utilizing iron oxide in converter slag is characterized by comprising the following steps:
s1, controlling the content of high ferric oxide in the slag at the early stage and the middle stage in the smelting process of the converter
Wherein:
the converter smelting is divided into three stages of an earlier stage, a middle stage and a later stage, the oxygen blowing smelting time of the converter is 15min, and the earlier stage is as follows: 0-5min, medium term: 5-12min, the early stage is: 12-15min;
the control of the lance position of the oxygen lance is divided into a low lance position, a middle lance position and a high lance position, wherein the range of the low lance position is as follows: 1.5-1.8m, and the range of the middle gun position is as follows: 1.8-2.5m, the high gun position range is as follows: 2.5-3.0m;
the converter bottom blowing gas supply intensity is designed to be 0.15Nm3T min, and simultaneously dividing the bottom blowing strength of the converter into high, medium and low bottom blowing strengths, wherein the low bottom blowing strength range is as follows: 0.02-0.05Nm3T min, the middle sole blowing strength range is as follows: 0.05-0.10Nm3T min, high bottom blowing intensity range: 0.10-0.15Nm3/t·min；
Controlling the angle of an oxygen lance nozzle of a medium-sized and small-sized converter which is less than 200 tons at 12-15 degrees, and controlling the angle of the oxygen lance nozzle of a large converter which is more than 200 tons at 14-16 degrees;
s1.1 method for controlling high ferric oxide content in early stage of converter
In the earlier stage of converter smelting, the lance position of an oxygen lance is controlled by alternately controlling a high lance position and a low lance position, the high lance position is controlled at first and then the low lance position, and the high lance position quickly improves the content of ferric oxide in slag to quickly reach more than 20 percent; then, the low lance position control is adopted, so that the temperature of a molten pool is uniformly raised as soon as possible, and meanwhile, the early low-temperature splashing of the converter is prevented; the bottom blowing strength control adopts middle-high bottom blowing gas supply strength for full stirring, the dynamic condition of a molten pool is improved, lime melting is promoted, and early-stage rapid slagging and dephosphorization are realized;
s1.2 method for controlling content of high ferric oxide in converter in middle period
In the middle stage of converter smelting, the lance position of the oxygen lance is controlled by adopting a middle lance position range, and the middle lance position and the high lance position are controlled alternately to keep the content of ferric oxide in slag to be between 18 and 25 percent; the long-time high lance position control is forbidden, so that the foam slag of the iron oxide slag with too high content is prevented from splashing; the gun position control is forbidden for a long time, and the gun return sticking and metal splashing of the iron oxide slag with too low content are prevented; the carbon-oxygen reaction of the molten pool is violent in the middle stage of smelting, the stirring intensity of the molten pool is sufficient, the bottom blowing intensity is controlled by adopting middle-low bottom blowing gas supply intensity to supplement stirring, the rapid melting of newly added lime is promoted, and the effects of rapid slag melting in the middle stage and dephosphorization in the early stage of protection are realized;
s2, controlling the content of low-iron oxide in the slag in the later period of the converter
In the later stage of converter smelting, the lance position of the oxygen lance is controlled by adopting a low lance position range, so that the content of iron oxide in slag is reduced, the content of the iron oxide is kept below 18 percent, the consumption of steel and iron materials is reduced, and the smelting cost is reduced; the long-time high lance position control in the later period is forbidden, so that the condition that the foam slag with over-high content of iron oxide slag cannot be subjected to the end-point carbon-drawing converter deslagging and tapping operation to influence the production of the converter and the occurrence of production accidents is prevented; in the later stage of smelting, the carbon-oxygen reaction of the molten pool is weakened, the stirring strength of the molten pool is reduced, the bottom blowing strength is controlled by adopting high bottom blowing gas supply strength to strengthen stirring, so that the content of iron oxide in the slag is reduced as soon as possible, and the low-cost production control target of low-iron-oxide slag in the later stage is realized.
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| CN104911295A (en) * | 2015-06-08 | 2015-09-16 | 北京科技大学 | Converter low-slag-added smelting method |
| CN110205437A (en) * | 2019-07-10 | 2019-09-06 | 攀钢集团攀枝花钢铁研究院有限公司 | The method for reducing TFe content in semi-steel making converter finishing slag |
| CN111363889A (en) * | 2020-03-20 | 2020-07-03 | 中天钢铁集团有限公司 | Efficient phosphorus removal method for combined blown converter |
| CN112111622A (en) * | 2019-06-21 | 2020-12-22 | 上海梅山钢铁股份有限公司 | Blowing method for converter with low molten iron consumption |
| CN113234886A (en) * | 2021-04-23 | 2021-08-10 | 甘肃酒钢集团宏兴钢铁股份有限公司 | Control method for realizing ultralow iron oxide of converter end-point slag |
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2021
- 2021-11-23 CN CN202111396165.1A patent/CN114032351B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104911295A (en) * | 2015-06-08 | 2015-09-16 | 北京科技大学 | Converter low-slag-added smelting method |
| CN112111622A (en) * | 2019-06-21 | 2020-12-22 | 上海梅山钢铁股份有限公司 | Blowing method for converter with low molten iron consumption |
| CN110205437A (en) * | 2019-07-10 | 2019-09-06 | 攀钢集团攀枝花钢铁研究院有限公司 | The method for reducing TFe content in semi-steel making converter finishing slag |
| CN111363889A (en) * | 2020-03-20 | 2020-07-03 | 中天钢铁集团有限公司 | Efficient phosphorus removal method for combined blown converter |
| CN113234886A (en) * | 2021-04-23 | 2021-08-10 | 甘肃酒钢集团宏兴钢铁股份有限公司 | Control method for realizing ultralow iron oxide of converter end-point slag |
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